/*
** $Id: loslib.c,v 1.17 2006/01/27 13:54:31 roberto Exp $
** Standard Operating System library
** See Copyright Notice in lua.h
*/


#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define loslib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

static int 
os_pushresult (lua_State *L, int i, const char *filename) 
{
	int en = errno;  /* calls to Lua API may change this value */
	if (i)
	{
		lua_pushboolean(L, 1);
		return 1;
	}
	else
	{
		lua_pushnil(L);
		if (filename)
			lua_pushfstring(L, "%s: %s", filename, strerror(en));
		else
			lua_pushfstring(L, "%s", strerror(en));
		lua_pushinteger(L, en);
		return 3;
	}
}


static int
os_execute (lua_State *L)
{
	lua_pushinteger(L, system(luaL_optstring(L, 1, NULL)));
	return 1;
}


static int
os_remove (lua_State *L)
{
	const char *filename = luaL_checkstring(L, 1);
	return os_pushresult(L, remove(filename) == 0, filename);
}


static int
os_rename (lua_State *L) 
{
	const char *fromname = luaL_checkstring(L, 1);
	const char *toname = luaL_checkstring(L, 2);
	return os_pushresult(L, rename(fromname, toname) == 0, fromname);
}


static int 
os_tmpname (lua_State *L) 
{
	char buff[LUA_TMPNAMBUFSIZE];
	int err;
	lua_tmpnam(buff, err);
	if (err)
		return luaL_error(L, "unable to generate a unique filename");
	lua_pushstring(L, buff);
	return 1;
}


static int 
os_getenv (lua_State *L) 
{
	lua_pushstring(L, getenv(luaL_checkstring(L, 1)));  /* if NULL push nil */
	return 1;
}


static int 
os_clock (lua_State *L)
{
	lua_pushnumber(L, ((lua_Number)clock())/(lua_Number)CLOCKS_PER_SEC);
	return 1;
}


/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

static void
setfield (lua_State *L, const char *key, int value) 
{
	lua_pushinteger(L, value);
	lua_setfield(L, -2, key);
}

static void 
setboolfield (lua_State *L, const char *key, int value)
{
	if (value < 0)  /* undefined? */
		return;  /* does not set field */
	lua_pushboolean(L, value);
	lua_setfield(L, -2, key);
}

static int
getboolfield (lua_State *L, const char *key)
{
	int res;
	lua_getfield(L, -1, key);
	res = lua_isnil(L, -1) ? -1 : lua_toboolean(L, -1);
	lua_pop(L, 1);
	return res;
}


static int
getfield (lua_State *L, const char *key, int d)
{
	int res;
	lua_getfield(L, -1, key);
	if (lua_isnumber(L, -1))
		res = (int)lua_tointeger(L, -1);
	else
	{
		if (d < 0)
			return luaL_error(L, "field " LUA_QS " missing in date table", key);
		res = d;
	}
	lua_pop(L, 1);

	return res;
}


static int
os_date (lua_State *L) 
{
	const char *s = luaL_optstring(L, 1, "%c");
	time_t t = lua_isnoneornil(L, 2) ? time(NULL) : (time_t)luaL_checknumber(L, 2);
	struct tm *stm;
	if (*s == '!')	/* UTC? */
	{  
		stm = gmtime(&t);
		s++;  /* skip `!' */
	}
	else
		stm = localtime(&t);

	if (stm == NULL)  /* invalid date? */
		lua_pushnil(L);
	else if (strcmp(s, "*t") == 0)
	{
		lua_createtable(L, 0, 9);  /* 9 = number of fields */
		setfield(L, "sec", stm->tm_sec);
		setfield(L, "min", stm->tm_min);
		setfield(L, "hour", stm->tm_hour);
		setfield(L, "day", stm->tm_mday);
		setfield(L, "month", stm->tm_mon+1);
		setfield(L, "year", stm->tm_year+1900);
		setfield(L, "wday", stm->tm_wday+1);
		setfield(L, "yday", stm->tm_yday+1);
		setboolfield(L, "isdst", stm->tm_isdst);
	}
	else
	{
		char b[256];
		if (strftime(b, sizeof(b), s, stm))
			lua_pushstring(L, b);
		else
			return luaL_error(L, LUA_QL("date") " format too long");
	}
	return 1;
}


static int 
os_time (lua_State *L)
{
	time_t t;
	if (lua_isnoneornil(L, 1))  /* called without args? */
		t = time(NULL);  /* get current time */
	else 
	{
		struct tm ts;
		luaL_checktype(L, 1, LUA_TTABLE);
		lua_settop(L, 1);  /* make sure table is at the top */
		ts.tm_sec = getfield(L, "sec", 0);
		ts.tm_min = getfield(L, "min", 0);
		ts.tm_hour = getfield(L, "hour", 12);
		ts.tm_mday = getfield(L, "day", -1);
		ts.tm_mon = getfield(L, "month", -1) - 1;
		ts.tm_year = getfield(L, "year", -1) - 1900;
		ts.tm_isdst = getboolfield(L, "isdst");
		t = mktime(&ts);
	}
	if (t == (time_t)(-1))
		lua_pushnil(L);
	else
		lua_pushnumber(L, (lua_Number)t);

	return 1;
}


static int 
os_difftime (lua_State *L) 
{
	lua_pushnumber(L, difftime((time_t)(luaL_checknumber(L, 1)), (time_t)(luaL_optnumber(L, 2, 0))));
	return 1;
}

/* }====================================================== */


static int 
os_setlocale (lua_State *L)
{
	static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME};
	static const char *const catnames[] = {"all", "collate", "ctype", "monetary", "numeric", "time", NULL};
	const char *l = lua_tostring(L, 1);
	int op = luaL_checkoption(L, 2, "all", catnames);
	luaL_argcheck(L, l || lua_isnoneornil(L, 1), 1, "string expected");
	lua_pushstring(L, setlocale(cat[op], l));

	return 1;
}


static int 
os_exit (lua_State *L)
{
	exit(luaL_optint(L, 1, EXIT_SUCCESS));
	return 0;  /* to avoid warnings */
}

static const luaL_Reg syslib[] = 
{
	{"clock",     os_clock},
	{"date",      os_date},
	{"difftime",  os_difftime},
	{"execute",   os_execute},
	{"exit",      os_exit},
	{"getenv",    os_getenv},
	{"remove",    os_remove},
	{"rename",    os_rename},
	{"setlocale", os_setlocale},
	{"time",      os_time},
	{"tmpname",   os_tmpname},
	{NULL, NULL}
};

/* }====================================================== */



LUALIB_API int 
luaopen_os (lua_State *L) 
{
	luaL_register(L, LUA_OSLIBNAME, syslib);
	return 1;
}

